1. Field of the Invention
The present invention relates to a technique capable of a two-dimensional (2D) scanning and a real time three-dimensional (3D) scanning, and more particularly to an ultrasonic diagnostic apparatus and an ultrasonic diagnostic method that emphatically displays a needle-tip portion of a puncture needle so that an operator can easily visually recognize a position of the needle-tip portion.
2. Description of the Related Art
An ultrasonic diagnostic apparatus is a medical diagnostic apparatus that noninvasively obtains tomograms of a soft tissue in a living body from a body surface using an ultrasonic pulse-echo method. The ultrasonic diagnostic apparatus has features that the apparatus is compact and inexpensive, has high safety with no exposure to X-rays, is capable of blood flow imaging, or the like as compared with other medical diagnostic apparatuses, and has been widely used in cardiac, abdominal, urology, obstetrics and gynecology departments, or the like.
The ultrasonic diagnostic apparatus is used not only for image diagnosis but also, for example, for radiofrequency ablation (RFA) as a local therapy of hepatocellular cancer or a biopsy for hepatocellular tissue examination. Such a therapy and an examination require precise puncture into a region of interest such as a tumor using a puncture needle. Thus, to clearly ascertain where the puncture needle enters in the living body, an ultrasonic diagnostic apparatus that can monitor the region of interest and the puncture needle in real time is used. Particularly, in recent years, the ultrasonic diagnostic apparatus sometimes uses real time three-dimensional ultrasonic images for display because of faster computers. In such a case, some methods have been proposed of displaying a puncture needle position on three-dimensional data during a puncture therapy, or marking a direction of a puncture needle (for example, Japanese Patent Application Publication (Laid-open: KOKAI) No. 6-205776). The ultrasonic diagnostic apparatus that is easy to use and capable of easy observation in real time is often used for a biopsy, or monitoring the needle-tip portion of a puncture needle and a lesion position in a local ablation therapy for cancer.
In recent years, an ultrasonic diagnostic apparatus capable of a real time volume scanning has also appeared. This apparatus can obtain needle position information in a slice direction of an ultrasonic probe, which has been hard to obtain, and is expected to increase accuracy of a biopsy or an ablation therapy.
However, the ultrasonic diagnostic apparatus in the related art sometimes has poor visibility because the visualized needle-tip portion of the puncture needle is buried in a background image, or the like, and places a burden on an operator. Also, because of uncertainty about the precise position of the needle-tip portion of the puncture needle, sufficient therapeutic effects may not be obtained such that tissue in a different position from the position of planned tissue is removed or an ablation therapy is performed in a different position.
When the ultrasonic diagnostic apparatus capable of the real time volume scanning is used, there is a problem that an expected effect cannot be obtained due to insufficient visibility of the needle-tip portion of the puncture needle.
Further, various studies have been made to increase visibility of a needle-tip portion of a puncture needle, and for example, there is a method using an image processing filter such as edge reinforcement. However, such a method has not been put to practical use because separation of only the needle-tip portion is difficult, and a substantial portion other than the needle-tip portion is influenced.